Piston



J. M. @RCKMYEW PISTON 2 Sheets-Sham E Film1 Jun@ l2@ 190W INVENTOR. JA.rocfmeJ/@r' BY a /1 TTOQ/VEY Patented Aug. 9, 1949 UNITED STATES PATENTOFFICE 6 Claims.

This invention relates to a piston of the type used in internalcombustion engines, pumps and the like, and the main object of theinvention is to produce an improved piston of this type.

A further object of the invention is to produce an improved constructionin which the piston is provided with a detachable head provided withparts ior receiving conventional piston rings so that, when the ringswear out, they may 'oe replaced with new ones by removing the detachablehead but without removing the piston itself from the cylinder.

it still iurther object oi the invention is to produce a pistonconstruction in which the heat dissipation is improved thus making forcooler operation, less breakdown oi the lubricant, and less wear.

il. still further object is to produce an improved construction in whichthe upper portion of the piston may be made lighter or of a relativelysmaller vertical cross-sectional thickness, as viewed in the drawings,without sacrificing its load capacity.

A stili further object is to improve the manner in which the detachablepiston head is secured to the piston body.

A still further object is to produce an improved construction whereby,when the worn out rings are replaced a new piston lit is achieved andwhereby this may be done at a relatively low cost in replacement partsand in effort.

These and other objects are attained by my invention as set forth in thefollowing specification and as illustrated in the accompanying drawingsin. which Fig. l is an exploded view of a piston embodying my invention.

Fig. 2 is a vertical sectional view of the piston shown assembled.

Fig. 3 is a top plan view of Fig. 2.

Fig. 4 is a side elevational view of the piston shown in Figs. l to 3.

Fig. 5 is a vertical sectional view showing an other embodiment of myinvention.

Fig. 6 is a view similar to Fig. 5 showing a slightly modiiiedstructure.

Fig. 7 is a top plan view of a clamping ring used in securing thedetachable head to the piston body in the embodiment of the inventionshown in Figs. l. to 4.

Fig. 8 is a top plan view of a clamping ring used in securing thedetachable head to the piston body in the embodiment of the inventionshown in Figs. 5 and 6.

Referring to Figs. 1 to 4, there is shown a plston having a cylindricallower skirt portion I il, and a frusto-conical reduced, upper headportion l2, the portions i0 and i2 being connected by a horizontalportion forming a shoulder it. The piston construction also includes asleeve it having exterior grooves it for receiving conventional splitrings til, the sleeve being internally tapered for a snug iit over thetruste-conical portion il.

Near its top surface 22, the upper portion il is provided with aperipheral groove lt for receiving the resilient split clamping ring 26of Fig. 7. The ring 2t is so made that, when free, it tends toconstrict. The juxtaposed ends of the rings 2t are provided with holesor recesses t@ adaped to be engaged-by an expanding type spanner wrenchfor applying or removing the ring. Thus, when it is desired to apply orremove the clamping ring, the points of the jaws of the Spanner wrenchare engaged in the recesses 28 and the handles of the wrench are movedin a direction to cause the jaws of the wrench to move apart, thusexpanding the clamping ring until it clears the groove 2l. The clampingring may now be removed from, or placed in the groove, as the case maybe.

The height of the sleeve i6, that is, the distance between broken linesA and B, and the height of the tapered upper portion I2, that is, thedistance between the broken lines C and D, in Fig. 1, are such, inrelation to the thickness of the clamping ring and the height of thegroove 24 that, when the sleeve i6 is slipped over the tapered portionI2 and the ring 26 is placed in the groove 24, as shown in Fig. 2, thesleeve will be pressed downwardly against the shoulder i4 and againstthe tapered surface of the portion i2 so that it is held rmly inposition against rotation relative to the piston. By this means, the oilholes 30 in the sleeve i6 will be maintained in proper registration withthe holes 32 in the piston portion l2. It will be understood that theupper surface 34 of the sleeve i6 and the upper surface 22 of thetapered portion I2 of the piston will be suitably indexed, as at 33, soas to insure initial alignment of the holes 30 in the of the uppersurface 22 l' sleeve, with the holes 32 in the piston portion I2 duringthe assembly of the piston.

When it is desired to renew the piston rings, the piston is moved to itsuppermost position, the clamping 26 is removed, and the piston islowered. When this is done the sleeve I6 is detached from the portion I2oi' the piston and remains in the upper portion of the cylinder fromwhich it can be readily removed. If the sleeve I6 should stick to thetop oi the piston and should move down with it, the piston is raised upagain, and the sleeve I6 is tapped with a wooden mallet, or the like, tobreak the bond between it and the top of the piston and the piston isagain lowered so as to leave the sleeve I6 at the upper end of thecylinder. In practice, I nd that this happens only infrequently. Whenthe sleeve has been removed, the piston is again raised and a new sleeveI6 having new rings 20 is then forced onto the tapered piston portion I2and is clamped in position by the ring 26. While it is possible merelyto replace the worn-out rings, I found, in practice, that it ispreferable to use a new sleeve I6 equipped with new rings 20 so as toprovide a new piston fit. This is due to the fact that when the groovesI8 wear somewhat, new rings placed in these grooves will be somewhatloosely seated y, and will, therefore, permit leakage and will causewear, particularly along the upper and. lower edges of the rings.

The taper of the upper piston portion I2 and of the sleeve I6 is suchthat the area of the upper surface 34 of the sleeve I6 exceeds the areaof the tapered piston portion I2. By this arrangement, the surface 22 ofthe portion I2 is subjected to a smaller portion of the force of theexplosion while the surface 34 of the sleeve I6 receives a largerportion of the force of the explosion. Because of this arrangement, theflat top of the upper piston portion can `be made thinner, in verticalcross section, without danger of breaking or of caving in. Because thesleeve I6 is supported on the relatively large surface area of thefrusto conical portion I2, which has the relatively thick wall 35, itcan withstand the major portion of the force of the explosion to whichit is subjected. The taper of the portion I2 and of the sleeve I6 isalso such as to produce a wedging frictional engagement of an ordersuicient to prevent rotation of the sleeve relative to the piston whenthe clamping ring 26 is in position, without the need of screws or thelike for securing the sleeve to the piston.

Furthermore, because the top of the tapered portion is of a relativelysmall diameter, it can be made of a thinner vertical cross section thanwould be otherwise possible.

Bymaking the area of the surface 34 of the sleeve I6 bigger than thearea of the top 22 of the piston, the sleeve will absorb a larger amountof heat than the piston and, because the sleeve I6 can dissipate itsheat more rapidly than the piston can, generally cooler operation willresult, thus reducing wear and tear on the contracting moving parts.

In Figs. and 6, there is shown a structure which is identical with thatof Figs. 1 and 2 except that the height of the sleeve is equal to theheight of the tapered portion I2, so that the surface 34 is flush withthe surface 22. To produce this structure, the upper surface 34 of thesleeve I6 is counter-bored, as at 40, to provide room for applicationand removal of a clamping ring.

In the structure of Fig. 5, I prefer to use a clamping ring 44, which isclearly shown in Fis. 8. This ring is made of two parts 4l and 46 whichare secured in assembled position by interlocking end lugs and recesses41. This type of ring does not need the room needed for applyins andremoving the ring 26, and no special wrench' is needed. The parts 45 and48 can be forced into position manually with the aid of a pair o!pliers, or the like, and can be disengaged by means of a screw driver orthe like.

Fig. 6 also shows that in the structure oi. Figs. 2130225 the top of thepiston can be concaved, as a It will thus be seen that, by providing theshoulder I4, the grooves 24 or 40, the clamping ring 26 and theseparable sleeve I6, and by tapering the upper portion I2 of the pistonand the sleeve I 6 to substantially the proportions shown in thedrawings, a light, strong and cool-operating piston is produced. It willalso be seen that the sleeve I6 and the ring 20 carried thereby may beremoved and installed as a unit and that the removal of the sleeve I6and the installation of a new sleeve, equipped with new rings, will havethe same effect as the installation of a complete new piston.

Having described my invention, what I claim is:

l. A piston comprising a lower cylindrical por tion, an upper,frusto-conical portion, a sleeve having an internal, frusto-conical boreadapted to t over said upper, frusto-conical portion, with at least theinner portion of the top wall of said sleeve disposed below the top wallof said frustoconical portion,said sleeve also having an outercylindrical surface adapted to form a continuation of the cylindricalsurface of the lower portion of the piston, and means for detachablysecuring said sleeve to said frusto-conical portion, said meansincluding a groove formed in said frusto-conical portion immediatelybelow the top wall thereof, with the bottom wall of said groovesubstantially flush with the inner adjacent portion of the top of saidsleeve, and a clamping means engaging said groove and said inner adrjacent portion of the top of said sleeve to prevent vertical movement ofsaid sleeve relative to said frusto-conical portion.

2. The structure recited in claim 1 in which said clampingmeans is asplit ring and in which the inner portion of said ring engages saidgroove and the outer portion of said ring overlies the inner adjacentportion of the top of said sleeve.

3. The structure recited in claim 1 in which the base of said upperfrusta-conical portion has a diameter smaller than the diameter of thelower cylindrical portion of the piston whereby a shoulder is formed ata right angle to the vertical axis of the piston.

4. The structure recited in claim 1 in which the outer portion of thetop of the sleeve, which is not engaged by said clamping means, is flushwith the top of said upper frusto-conical portion of the piston.

5. A piston comprising a lower skirt portion, an upper frusto-conicalhead portion, a sleeve having a tapered internal bore adapted to t oversaid head portion and having an external surface adapted to form acontinuation of the surface "of said skirt portion, the taper of saidhead portion being such that the area of the top surface of said headportion is less than the area of the top surface of said sleeve, andmeans for securing said sleeve to said head portion.

6. A piston comprising a lower skirt portion, an upper. hollow headportion formed of a irustoamarre 5 conical wall structure and end wallat the smaller REFERENCES CITED end of said frusto-conical wallstructure, an an- The following referentes are of record in the nularsleeve having an external surface adapted me of this patent; to form acontinuation of the external surface TES of said skirt portion andhaving a tapered bore s UNITED STA PATENTS JOSEPH A. BR()CK1ME1YER2,369,906 MOOle Feb. 20, 1945

